1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![allow(non_camel_case_types, non_snake_case)]
13 //! Code that is useful in various codegen modules.
16 use llvm::{ValueRef, ContextRef, TypeKind};
17 use llvm::{True, False, Bool, OperandBundleDef};
18 use rustc::hir::def_id::DefId;
19 use rustc::middle::lang_items::LangItem;
26 use type_of::LayoutLlvmExt;
28 use rustc::ty::{self, Ty, TyCtxt};
29 use rustc::ty::layout::{HasDataLayout, LayoutOf};
32 use libc::{c_uint, c_char};
35 use rustc_target::spec::abi::Abi;
36 use syntax::symbol::LocalInternedString;
37 use syntax_pos::{Span, DUMMY_SP};
39 pub use context::CodegenCx;
41 pub fn type_needs_drop<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> bool {
42 ty.needs_drop(tcx, ty::ParamEnv::reveal_all())
45 pub fn type_is_sized<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> bool {
46 ty.is_sized(tcx.at(DUMMY_SP), ty::ParamEnv::reveal_all())
49 pub fn type_is_freeze<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> bool {
50 ty.is_freeze(tcx, ty::ParamEnv::reveal_all(), DUMMY_SP)
54 * A note on nomenclature of linking: "extern", "foreign", and "upcall".
56 * An "extern" is an LLVM symbol we wind up emitting an undefined external
57 * reference to. This means "we don't have the thing in this compilation unit,
58 * please make sure you link it in at runtime". This could be a reference to
59 * C code found in a C library, or rust code found in a rust crate.
61 * Most "externs" are implicitly declared (automatically) as a result of a
62 * user declaring an extern _module_ dependency; this causes the rust driver
63 * to locate an extern crate, scan its compilation metadata, and emit extern
64 * declarations for any symbols used by the declaring crate.
66 * A "foreign" is an extern that references C (or other non-rust ABI) code.
67 * There is no metadata to scan for extern references so in these cases either
68 * a header-digester like bindgen, or manual function prototypes, have to
69 * serve as declarators. So these are usually given explicitly as prototype
70 * declarations, in rust code, with ABI attributes on them noting which ABI to
73 * An "upcall" is a foreign call generated by the compiler (not corresponding
74 * to any user-written call in the code) into the runtime library, to perform
75 * some helper task such as bringing a task to life, allocating memory, etc.
79 /// A structure representing an active landing pad for the duration of a basic
82 /// Each `Block` may contain an instance of this, indicating whether the block
83 /// is part of a landing pad or not. This is used to make decision about whether
84 /// to emit `invoke` instructions (e.g. in a landing pad we don't continue to
85 /// use `invoke`) and also about various function call metadata.
87 /// For GNU exceptions (`landingpad` + `resume` instructions) this structure is
88 /// just a bunch of `None` instances (not too interesting), but for MSVC
89 /// exceptions (`cleanuppad` + `cleanupret` instructions) this contains data.
90 /// When inside of a landing pad, each function call in LLVM IR needs to be
91 /// annotated with which landing pad it's a part of. This is accomplished via
92 /// the `OperandBundleDef` value created for MSVC landing pads.
95 operand: OperandBundleDef,
99 pub fn new(cleanuppad: ValueRef) -> Funclet {
102 operand: OperandBundleDef::new("funclet", &[cleanuppad]),
106 pub fn cleanuppad(&self) -> ValueRef {
110 pub fn bundle(&self) -> &OperandBundleDef {
115 pub fn val_ty(v: ValueRef) -> Type {
117 Type::from_ref(llvm::LLVMTypeOf(v))
121 // LLVM constant constructors.
122 pub fn C_null(t: Type) -> ValueRef {
124 llvm::LLVMConstNull(t.to_ref())
128 pub fn C_undef(t: Type) -> ValueRef {
130 llvm::LLVMGetUndef(t.to_ref())
134 pub fn C_int(t: Type, i: i64) -> ValueRef {
136 llvm::LLVMConstInt(t.to_ref(), i as u64, True)
140 pub fn C_uint(t: Type, i: u64) -> ValueRef {
142 llvm::LLVMConstInt(t.to_ref(), i, False)
146 pub fn C_uint_big(t: Type, u: u128) -> ValueRef {
148 let words = [u as u64, (u >> 64) as u64];
149 llvm::LLVMConstIntOfArbitraryPrecision(t.to_ref(), 2, words.as_ptr())
153 pub fn C_bool(cx: &CodegenCx, val: bool) -> ValueRef {
154 C_uint(Type::i1(cx), val as u64)
157 pub fn C_i32(cx: &CodegenCx, i: i32) -> ValueRef {
158 C_int(Type::i32(cx), i as i64)
161 pub fn C_u32(cx: &CodegenCx, i: u32) -> ValueRef {
162 C_uint(Type::i32(cx), i as u64)
165 pub fn C_u64(cx: &CodegenCx, i: u64) -> ValueRef {
166 C_uint(Type::i64(cx), i)
169 pub fn C_usize(cx: &CodegenCx, i: u64) -> ValueRef {
170 let bit_size = cx.data_layout().pointer_size.bits();
172 // make sure it doesn't overflow
173 assert!(i < (1<<bit_size));
176 C_uint(cx.isize_ty, i)
179 pub fn C_u8(cx: &CodegenCx, i: u8) -> ValueRef {
180 C_uint(Type::i8(cx), i as u64)
184 // This is a 'c-like' raw string, which differs from
185 // our boxed-and-length-annotated strings.
186 pub fn C_cstr(cx: &CodegenCx, s: LocalInternedString, null_terminated: bool) -> ValueRef {
188 if let Some(&llval) = cx.const_cstr_cache.borrow().get(&s) {
192 let sc = llvm::LLVMConstStringInContext(cx.llcx,
193 s.as_ptr() as *const c_char,
195 !null_terminated as Bool);
196 let sym = cx.generate_local_symbol_name("str");
197 let g = declare::define_global(cx, &sym[..], val_ty(sc)).unwrap_or_else(||{
198 bug!("symbol `{}` is already defined", sym);
200 llvm::LLVMSetInitializer(g, sc);
201 llvm::LLVMSetGlobalConstant(g, True);
202 llvm::LLVMRustSetLinkage(g, llvm::Linkage::InternalLinkage);
204 cx.const_cstr_cache.borrow_mut().insert(s, g);
209 // NB: Do not use `do_spill_noroot` to make this into a constant string, or
210 // you will be kicked off fast isel. See issue #4352 for an example of this.
211 pub fn C_str_slice(cx: &CodegenCx, s: LocalInternedString) -> ValueRef {
213 let cs = consts::ptrcast(C_cstr(cx, s, false),
214 cx.layout_of(cx.tcx.mk_str()).llvm_type(cx).ptr_to());
215 C_fat_ptr(cx, cs, C_usize(cx, len as u64))
218 pub fn C_fat_ptr(cx: &CodegenCx, ptr: ValueRef, meta: ValueRef) -> ValueRef {
219 assert_eq!(abi::FAT_PTR_ADDR, 0);
220 assert_eq!(abi::FAT_PTR_EXTRA, 1);
221 C_struct(cx, &[ptr, meta], false)
224 pub fn C_struct(cx: &CodegenCx, elts: &[ValueRef], packed: bool) -> ValueRef {
225 C_struct_in_context(cx.llcx, elts, packed)
228 pub fn C_struct_in_context(llcx: ContextRef, elts: &[ValueRef], packed: bool) -> ValueRef {
230 llvm::LLVMConstStructInContext(llcx,
231 elts.as_ptr(), elts.len() as c_uint,
236 pub fn C_array(ty: Type, elts: &[ValueRef]) -> ValueRef {
238 return llvm::LLVMConstArray(ty.to_ref(), elts.as_ptr(), elts.len() as c_uint);
242 pub fn C_vector(elts: &[ValueRef]) -> ValueRef {
244 return llvm::LLVMConstVector(elts.as_ptr(), elts.len() as c_uint);
248 pub fn C_bytes(cx: &CodegenCx, bytes: &[u8]) -> ValueRef {
249 C_bytes_in_context(cx.llcx, bytes)
252 pub fn C_bytes_in_context(llcx: ContextRef, bytes: &[u8]) -> ValueRef {
254 let ptr = bytes.as_ptr() as *const c_char;
255 return llvm::LLVMConstStringInContext(llcx, ptr, bytes.len() as c_uint, True);
259 pub fn const_get_elt(v: ValueRef, idx: u64) -> ValueRef {
261 assert_eq!(idx as c_uint as u64, idx);
262 let us = &[idx as c_uint];
263 let r = llvm::LLVMConstExtractValue(v, us.as_ptr(), us.len() as c_uint);
265 debug!("const_get_elt(v={:?}, idx={}, r={:?})",
266 Value(v), idx, Value(r));
272 pub fn const_get_real(v: ValueRef) -> Option<(f64, bool)> {
274 if is_const_real(v) {
275 let mut loses_info: llvm::Bool = ::std::mem::uninitialized();
276 let r = llvm::LLVMConstRealGetDouble(v, &mut loses_info as *mut llvm::Bool);
277 let loses_info = if loses_info == 1 { true } else { false };
278 Some((r, loses_info))
285 pub fn const_to_uint(v: ValueRef) -> u64 {
287 llvm::LLVMConstIntGetZExtValue(v)
291 pub fn is_const_integral(v: ValueRef) -> bool {
293 !llvm::LLVMIsAConstantInt(v).is_null()
297 pub fn is_const_real(v: ValueRef) -> bool {
299 !llvm::LLVMIsAConstantFP(v).is_null()
305 fn hi_lo_to_u128(lo: u64, hi: u64) -> u128 {
306 ((hi as u128) << 64) | (lo as u128)
309 pub fn const_to_opt_u128(v: ValueRef, sign_ext: bool) -> Option<u128> {
311 if is_const_integral(v) {
312 let (mut lo, mut hi) = (0u64, 0u64);
313 let success = llvm::LLVMRustConstInt128Get(v, sign_ext,
314 &mut hi as *mut u64, &mut lo as *mut u64);
316 Some(hi_lo_to_u128(lo, hi))
326 pub fn langcall(tcx: TyCtxt,
331 match tcx.lang_items().require(li) {
334 let msg = format!("{} {}", msg, s);
336 Some(span) => tcx.sess.span_fatal(span, &msg[..]),
337 None => tcx.sess.fatal(&msg[..]),
343 // To avoid UB from LLVM, these two functions mask RHS with an
344 // appropriate mask unconditionally (i.e. the fallback behavior for
345 // all shifts). For 32- and 64-bit types, this matches the semantics
346 // of Java. (See related discussion on #1877 and #10183.)
348 pub fn build_unchecked_lshift<'a, 'tcx>(
349 bx: &Builder<'a, 'tcx>,
353 let rhs = base::cast_shift_expr_rhs(bx, hir::BinOp_::BiShl, lhs, rhs);
354 // #1877, #10183: Ensure that input is always valid
355 let rhs = shift_mask_rhs(bx, rhs);
359 pub fn build_unchecked_rshift<'a, 'tcx>(
360 bx: &Builder<'a, 'tcx>, lhs_t: Ty<'tcx>, lhs: ValueRef, rhs: ValueRef
362 let rhs = base::cast_shift_expr_rhs(bx, hir::BinOp_::BiShr, lhs, rhs);
363 // #1877, #10183: Ensure that input is always valid
364 let rhs = shift_mask_rhs(bx, rhs);
365 let is_signed = lhs_t.is_signed();
373 fn shift_mask_rhs<'a, 'tcx>(bx: &Builder<'a, 'tcx>, rhs: ValueRef) -> ValueRef {
374 let rhs_llty = val_ty(rhs);
375 bx.and(rhs, shift_mask_val(bx, rhs_llty, rhs_llty, false))
378 pub fn shift_mask_val<'a, 'tcx>(
379 bx: &Builder<'a, 'tcx>,
384 let kind = llty.kind();
386 TypeKind::Integer => {
387 // i8/u8 can shift by at most 7, i16/u16 by at most 15, etc.
388 let val = llty.int_width() - 1;
390 C_int(mask_llty, !val as i64)
392 C_uint(mask_llty, val)
395 TypeKind::Vector => {
396 let mask = shift_mask_val(bx, llty.element_type(), mask_llty.element_type(), invert);
397 bx.vector_splat(mask_llty.vector_length(), mask)
399 _ => bug!("shift_mask_val: expected Integer or Vector, found {:?}", kind),
403 pub fn ty_fn_sig<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
405 -> ty::PolyFnSig<'tcx>
409 // Shims currently have type TyFnPtr. Not sure this should remain.
410 ty::TyFnPtr(_) => ty.fn_sig(cx.tcx),
411 ty::TyClosure(def_id, substs) => {
413 let sig = substs.closure_sig(def_id, tcx);
415 let env_ty = tcx.closure_env_ty(def_id, substs).unwrap();
416 sig.map_bound(|sig| tcx.mk_fn_sig(
417 iter::once(*env_ty.skip_binder()).chain(sig.inputs().iter().cloned()),
424 ty::TyGenerator(def_id, substs, _) => {
426 let sig = substs.poly_sig(def_id, cx.tcx);
428 let env_region = ty::ReLateBound(ty::DebruijnIndex::new(1), ty::BrEnv);
429 let env_ty = tcx.mk_mut_ref(tcx.mk_region(env_region), ty);
431 sig.map_bound(|sig| {
432 let state_did = tcx.lang_items().gen_state().unwrap();
433 let state_adt_ref = tcx.adt_def(state_did);
434 let state_substs = tcx.mk_substs([sig.yield_ty.into(),
435 sig.return_ty.into()].iter());
436 let ret_ty = tcx.mk_adt(state_adt_ref, state_substs);
438 tcx.mk_fn_sig(iter::once(env_ty),
441 hir::Unsafety::Normal,
446 _ => bug!("unexpected type {:?} to ty_fn_sig", ty)